Does chapter 19 describe any of Sai Baba's interactions with other known saints, like Guru Nanak?

Based on the provided text, Chapter 19 does not describe any interactions between Sai Baba and Guru Nanak or any other specific named saints. The focus is more on the abstract nature of the Guru's power and the devotee's path. The chapter states that to gain "Guru-strength like Sai’s, strong fortune is necessary." It also encourages the devotee to surrender with an undivided heart to "witness the wonder of devotion" and experience the "new marvels of Sai's skill." The guidance in Chapter 19 is about the universal Guru-disciple dynamic rather than historical interactions.